Why radiators / heaters with heat pump are often efficient?
Radiators or radiators with the heat pump as a heating system do not have a good reputation. Unlike conventional heating systems based on fossil fuels, heat pumps use energy stored in the air, soil or water. They convert this energy into heat, which is then delivered to the radiators in the home. Unlike fossil fuel combustion at several hundred degrees Celsius, every degree of heating matters here. Because radiators like radiators tend to require a lot of heating, heat pumps were long considered unsuitable for this heat delivery. With the further development of heat pump technology, however, this is no longer true. In fact, the better a heat pump can reach higher temperatures, the easier it is to operate radiators.
So if your building currently has radiators installed, you do not need to replace them with underfloor heating at a high cost. Instead, first calculate the necessary flow temperature and efficiency of the heat pump. If the system achieves an average heat transfer efficiency of 3 or higher at the required flow temperature, the combination with radiators could already be worthwhile. Of course, the efficiency would increase further with the installation of a more extensive heating output, but this is not always feasible and worthwhile.
How does a heat pump work in conjunction with radiators / radiators?
A heat pump works much like a refrigerator, only backwards. It extracts heat from the environment (air, water or earth) and transfers it to your heating system. For the efficiency of the machine it is essential which temperature difference between source temperature (air, water or earth) and output temperature (flow temperature) prevails. This difference is referred to as the delta T (ΔT). The colder it is outside and the hotter the water in radiators/floor heating has to be, the more energy is used. Conversely, the heating becomes more efficient if the supply temperature can be lowered. Of course, we cannot influence source temperatures. But if the supply temperature is simply lowered, then it will be cooler in the room. However, there is a trick: if the surface area of the heat dissipation system is very large, then the heat is dissipated more quickly into the room. Therefore, the larger the delivery system, the lower the supply temperature can be and thus the energy expenditure.
This is why underfloor heating systems are so efficient. Distributed snake-like over the entire floor, these pipes provide a huge surface through which the heating water flows at a relatively low temperature. Classic radiators are much smaller, so they have a correspondingly smaller surface area, which means that a higher flow temperature is required for the same room temperature. However, as we have noticed, this also means that the delta T becomes larger and the energy costs increase.
Nevertheless, it must be noted that the simple comparison of underfloor heating and radiators is not over yet. Different underfloor heating systems and different radiators also have different surfaces. If your room is plastered with huge radiators, then the flow temperature may actually be lower than with underfloor heating. However, with past experience or the help of a heating engineer, it is easy to calculate the necessary flow temperature. How efficiently a heat pump delivers this calculated flow temperature is independent of whether the delivery system is underfloor heating or radiators, as long as the water flows through at the same temperature. Because the mode of operation is basically the same.
Optimal use of radiators / radiators with heat pump
With existing, smaller radiators, the heat pump may not reach its full efficiency because the flow temperature is relatively high. However, modern heat pumps are designed to work with higher flow temperatures, and only a little more energy is lost. The NovaAir, for example, still achieves a SCOP of 3.93 even for the high supply temperature of 55°C. A few years ago, this would have made it one of the more efficient machines even for heating an underfloor heating system. If the flow temperature is reduced to 35°C, the electricity requirement is reduced by over 20%. So if the existing radiators cannot be replaced by underfloor heating, a heat pump can still pay off.
However, an option is also the installation of so-called low-temperature radiators, which are also called heat pump radiators. Low-temperature radiators have a larger heating surface than conventional radiators, which reduces the flow temperature. This allows them to evenly transfer the heat of the heating water to the air in the room. Therefore, large-area radiators are ideal in combination with heat pumps. Unlike underfloor heating, they are less complicated to install. However, there must still be enough space on the walls in the building for their placement.
In order to efficiently use radiators with a heat pump, there are a few key points to consider. The heat pump must be properly sized to work efficiently. It is recommended to take care not to set the temperature too high - a lower temperature is often sufficient and saves energy. Similarly, radiators should not be covered by furniture or curtains to ensure optimal heat dissipation. In addition, good insulation of the house can significantly reduce heating requirements.
When using a heat pump with radiators, a few more tips can be followed to maximize heating efficiency.
4 tips for maximum heating efficiency with radiators
1. low temperature radiator
Low temperature radiators are ideal for operation with heat pumps. They have a larger heating surface than conventional radiators, which means that the heat from the heating water is transferred more evenly to the air in the room.
2. correct setting of the flow temperature
The flow temperature is the temperature of the water flowing through the radiators. For heat pump operation, the lower the flow temperature, the more efficient the operation. In any case, make sure that the heat pump's COP is at least 3 at the required flow temperature.
3. regular maintenance
Regular maintenance of your heat pump helps maintain its efficiency. Your heating engineer or installer can help you keep your heat pump in good shape.
4Regular shock ventilation
Ventilation is the process of removing warm air from the house. Be sure to ventilate regularly to keep the humidity in your home low. But do this only in short bursts so that the heat pump does not have to heat up against the cold air outside.
What are the advantages & disadvantages of combining heat pump and radiators / radiators?
The combination of heat pump and radiators offers many advantages but also disadvantages. Especially for existing buildings with radiators, the combination with a heat pump is a good way to improve energy efficiency and save on heating costs without having to tear out existing radiators and expensive new installation of underfloor heating.
Below are listed in detail the main advantages and disadvantages of the combination of heat pump and radiators / radiators:
Advantages
Inexpensive to purchase:
Radiators are a cost-effective option when choosing a heating system. Compared to underfloor heating, the initial cost is usually lower and, most importantly, retrofitting is easier. In a new building, however, underfloor heating should be installed in any case. It will pay for itself after just a few years.
Flexible use:
Radiators are extremely flexible in their application. They can be installed in virtually any room, regardless of its size or shape. This versatility makes it possible to tailor heating solutions to the individual needs of a house or apartment. Especially when another radiator lowers the heat output enough that only one heat pump needs to be installed instead of two machines, the retrofit is worthwhile.
Simple:
In general, radiators require little attention and regular cleaning to function properly. This makes them a practical choice for people looking for an uncomplicated heating solution that you can even perform the maintenance yourself with a little practice.
Long life:
Radiators are characterized by their long service life and can last up to 20 years or more if properly maintained. This longevity means they represent a long-term investment in a building's heating system and reduce the need for frequent replacements.
Disadvantages
Uneven heat distribution:
Radiators and radiators give off heat mainly by convection. This means that the air at the radiator is heated and then rises. The air at the bottom, on the other hand, remains cold. This can lead to an uneven feeling of warmth in the rooms.
High flow temperature:
Radiators and radiators usually require higher flow temperatures of 50 to 60 degrees Celsius to ensure sufficient heat output. This can lead to higher electricity costs.
Space requirements:
Radiators and heaters are space-consuming in their design. This means that they take up a certain amount of space in a room, which can cause space problems in small or cramped rooms. The need to keep wall space free for installation can limit room design and affect the arrangement of furniture and decorations. In such cases, it is important to carefully plan the placement of radiators to ensure the functionality and aesthetics of the room.
Pollution:
Radiators and heaters can become clogged with dust and dirt over time. This can affect the efficiency of the heating system, as dirt can hinder heat transfer. Therefore, it is advisable to clean radiators regularly to ensure that they are working optimally. Regular maintenance also helps to improve the air quality in the room, as fewer dust particles are released into the air.
Noise generation:
Radiators and heaters can cause noise, especially when they are switched on and the warm water flows through the pipes. This noise can be disturbing in quiet rooms or during the night. It is important to note that modern heating systems are often quieter than older models. Nevertheless, it is advisable to use soundproofing techniques to minimize possible disturbances, especially in bedrooms or living rooms where quiet and comfort are important.
How can the efficiency of the heating be further improved?
If you want to increase the efficiency of heating with heat pump, there are some tips that should be followed.
First, install a heat pump with a high COP value - such as the NovaAir - because it produces more heat for less electricity. Proper maintenance of the heat pump must be ensured to optimize performance. Temperature controllers can be used to precisely control the room temperature and avoid unnecessary heating. The lower the supply temperature, the more efficiently the heat pump will operate. In addition, the radiators should be large enough to distribute the heat effectively.
Set room temperature
The room temperature should be set correctly, and the ideal room temperature differs depending on the user and use. But remember: every degree less saves up to 6% heating energy on average.
Placement of radiators
The radiators should be adjusted so that the heat is evenly distributed in the room. The positioning also plays an important role.
Insulation
Good home insulation helps minimize heat loss, which means the heating system has to work less to heat the home. If solar panels are present, use solar energy to heat the house and produce hot water.
Switch off regularly
Turn off the heating when leaving the house to avoid unnecessary energy consumption. Ideally, this can be programmed from the heat pump control.
Selection criteria of radiators / radiators for a heat pump
When purchasing radiators or radiators for your heat pump, there are several important considerations to take into account. It is advisable to choose models designed for low flow temperatures, as heat pumps achieve their maximum efficiency when operating at low temperature. Of course, this is only true if you have enough floor space to make it worthwhile. In addition, large-area radiators play a crucial role, as they distribute heat more evenly. The quality of the radiator's thermal insulation is also of great importance in minimizing heat loss.
Flow temperature
Heatpumps operate most efficiently at low flow temperatures s. Therefore, the radiators should be suitable for operation at low flow temperatures. In old buildings with inefficient, smaller radiators, however, flow temperatures of 55 degrees Celsius may be required quickly. Although this results in comparatively higher power consumption by the heat pump, it can be easily achieved, especially with highly efficient heat pumps such as the NovaAir air/water heat pump.
Sufficient heating power
The heating capacity of the radiators should be sufficient to heat the rooms. You can calculate the heating capacity based on the size and insulation of your house or hire an energy consultant to determine exact values and get an optimal decision basis and recommendation.
High energy efficiency
Before making a final selection, it is essential to check the energy efficiency class of the radiator. A higher class indicates a more efficient heating solution. Finally, it is advisable to consult a professional to ensure that the chosen radiator harmonizes optimally with your heat pump.
Design
The radiators should also match your interior style. Nowadays there is a wide range of radiators in different shapes and colors.
Conclusion
In conclusion, the use of radiators and radiators even in combination with a heat pump is an efficient heating solution. This method is not only environmentally friendly, but also cost-saving. Above all, it is important to choose the right heat pump, which can also efficiently provide higher flow temperatures. This ensures a comfortable indoor climate. It is important to set the heat pump correctly and maintain it regularly for optimal performance. With an intelligent control system, you can reduce energy consumption even further. This allows you to heat your home efficiently and comfortably.
